Workability in the coating with a trowel of a hydraulic composition such as plastering material has been realized by adding a natural seaweed glue such as the one prepared form Chondrus ocellatus. Since the development of methylcellulose (a semi-synthetic resin), it has been commonly used for providing the workability.
The properties required for the hydraulic composition include good workability (ease of coating and finishing), high water retention (prevention of curing failure caused, for example, by drying out), and resistance to sagging (moving) (prevention of the coated mortal from deformation by its own weight and prevention of adhered tile from moving), and even severer requirements are imposed with the recent streamlining of the workplace.
JP-A 11-349367 (Patent Document 1) discloses a method for use in the field of concretes, and this method uses a combination of AE (air entraining) agent which is an anionic surfactant and a shrinkage reducing agent such as a polyoxyalkylene copolymer. When the content disclosed in the JP-A 11-349367 for the concretes is used in the present invention, the excessively high content results in the significant loss of workability as well as inferior properties of the cured product, and the object of the present invention is never realized.